Tire mold



IVI. A. MARQUETTE.

11m-2 MOLD.

l APPLICATION FILED NOV. 24,1920.

Patented J une 13, 1922a r'queIIe NTO MC1 BYv ATToR Y INVE Mav'on H.

' amasar. y'

entre srsV` Mnnvon- A. MARQUET'TE, or cHIcorEE FALLS, 1v1AssAo-1fiusn'r'rs, ASSIGNOR 'ro THE Parar erstes.. A

FISE RUBBER COMPANY, CHICOPEE FALLS, MASSACHUSETTS, A CORORATION or MASSACHUSETTS.

To aZZ whomz't may concern.'

Be it known that I, MnLvoN` A. MAR- flf .QUE'1'rE, a citizen of the United, States of .v America, residin at Chicopee Falls,.in the county, of Hamp en and State ofMassachusettsfhave invented`certain new and useful' Improvementsin Tire Molds, of ywhich the following isa specification. A

This" invention relates to an particularly to tires made by the full' molded method. Usually tires are molded by loeating a metal core, with the carcass and" tread bilt thereon, within a cast iron mold and applying pressure and heat to cause complete shaping'- and vulcanization of the tire. l l l In a full molded tire, a common source of weakness occurs in the 'form of a buckle above the bead which is caused by the o'w of rubber. from two directions'meetingand pulling the fabric out of its proper alignment around the core. In order to form a clear cut tread and dueto the placing of excessive stock at certain parts of the tire when built on the core, the bearing action between the core, with thev tire built 'onit, and `the mold is such that as the core islaid in the mold, there are two points of contact between the tire and the moldl on each halfsection, one at a point near the lower side wall portion of the tread and the other at the bead. As themolds close, a pressure is gradually exerted from the irst point of contact to the top of the tread, pushing ahead of it a wave of rubber which fills the treadv,

'fabric up in a buckle, which is afterwards pressed down out of its natural alignment.

Another considerationis the ressure to which a-carcass is subjected while being vulcanized. Too high a' pressure will greatly impair the tensile and resilient qualities, of

vwhenever possible.

TIRE MOLD.

` the strain-resisting members of the carcass.

A study of the normal components between l Patented Jane 13,1922. 'Application mea November 24, 1926. serial No. 426,181.

which the carcass is compressed, together with what .consideration can be--Lgivenxdue to the padding action of thin and thick layers of rubber, shows'that the greatest compression -comes at the middle of the side wall.

. I Itis therefore very essential to prevent exapparatus for .making pneumatic ltire casings and more cessive pressure at this and adjacent points The object'of this invention is to provide amold which "will substantially eliminate any tendency. toward buckling above the bead, as well as relieve excessive pressure on the side walls, and which .willhave all the good molding-qualities of an ordinary cast lron mold.

Fig. lV shows amold in plan view, partially the tread forming portion 7 v.of thel mold is the excessive stock outlet pocket 8. Dowel pins, whlch hold the molds in `position one to another are' shown in dotted lines 9 while the recesses 10 are cut into the mold periphery every 90 to attach the lugs which pull the molds apart. The annular insert 4 which is 'the' feature of this invention is shown inA its position in the mold inner surface, extending from a point at the bottom of tread forming portion of mold 11, to av vpoint just above the heel of the bead, the insert not being carried to the base of the bead sinceV rigid mold portions cut a more clearly defined base.

As seen at A, Fig. 2, the Yupper face of the ring preferabl extendsslightly beyond the adjacent insi e contour 'of the mold. When the tire and core are inserted and the molds closed but not placed under high pressure, the first points of bearing will be approximately at B, Fig. 2 and at the bead of the tire. Buckling. above the bead will be practically eliminated because insteadof an excessive pressure being exerted on the first two contact points-which increases on magnitudel as the, moldsl close as well as extends its' bearing area slowly toward the fio .which tend to buckle' the `fabric.

side Wall center, ahead of it; there will be a compression of the -insert atv the first bearing points with a rapld increase in bearing surface so that before any excessive pressure is exerted at' core, and the working ability of the sub? `stance to stand up under -itshard usage.

The preferred material is,-l1ovvever` vulcanized rubber fabric. Since there are many' Widely different embodi "tents of this inven- R m the spirit ofit,

tien' Without departing myselfV to any -spepushing waves of rubber -terial conforming to a cific form of location or shape of the annular inserts except as specifically pointed out in the followingclaims. In particular, if a non-sliid tread is not to be formed, it may be found desirable to locate the compressible portion of the mold at the tread rather than adjacent the beads.

Having thus described my invention, I claim:

l. A tire'mold, having annular concave inside faces, annular grooves of substantial Width and thickness cut in said faces, and annular ringsof a firm but compressible material inserted in said grooves.

2. A tire mold having an inner face comprising a Hrm but easily compressible maportion of the `inner contour of the mold. y A

3. A tire mold havinga 'rigid tread form,- ing portion and a vyielding side Wall portion. n' 4. A tire mold comprising a firm but compressible side Wall and-bead forming portion Whose 4inside contour protrudes from the adjacent inside contour of the mold.

M. A. MARQUETTE. 

